Mattermost Desktop App versions <=5.8.0 fail to sufficiently configure Electron Fuses which allows an attacker to gather Chromium cookies or abuse other misconfigurations via remote/local access.

Mattermost Desktop App versions <=5.8.0 fail to safeguard screen capture functionality which allows an attacker to silently capture high-quality screenshots via JavaScript APIs.

Mattermost Desktop App versions <=5.7.0 fail to correctly prompt for permission when opening external URLs which allows a remote attacker to force a victim over the Internet to run arbitrary programs on the victim's system via custom URI schemes.

Mattermost Desktop fails to correctly handle permissions or prompt the user for consent on certain sensitive ones allowing media exploitation from a malicious mattermost server

Mattermost fails to properly validate a RegExp built off the server URL path, allowing an attacker in control of an enrolled server to mount a Denial Of Service.

Mattermost Desktop fails to set an appropriate log level during initial run after fresh installation resulting in logging all keystrokes including password entry being logged.

Mattermost Desktop App fails to validate a mattermost server redirection and navigates to an arbitrary website

An issue was discovered in Mattermost Desktop App before 4.0.0. It mishandled the Same Origin Policy for setPermissionRequestHandler (e.g., video, audio, and notifications).

An issue was discovered in Mattermost Desktop App before 4.4.0. Prompting for HTTP Basic Authentication is mishandled, allowing phishing, aka MMSA-2020-0007.

An issue was discovered in Mattermost Desktop App before 4.4.0. Attackers can open web pages in the desktop application because server redirection is mishandled, aka MMSA-2020-0008.